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Patent Information & Production OptionsSpiral Elastic Folder with Magnetic Closure and Sliding Clamp · Patent CN112519448B

Patent CN112519448B: bibliographic data, legal status, family, a plain-language reading of the claims, plus customization, US compliance points and how a manufacturing project runs.

At a glance

Patent numberCN112519448B (application CN202011512409)
TypeChina invention patent (发明专利) - protects new technical solutions
Original titleFolder convenient to store (一种收纳方便的文件夹)
Patent ownerShandong Lunan Big Data Industry Development Co ltd
InventorsZhang Qi, Gao Yang, Wang Hui, Li Yimin
Filing date2020-12-19
Grant date2022-02-22
Status (China)In force - valid until at most 2040-12-19, subject to payment of annual fees
Patent familyChinese filings only - no US, European, Japanese, PCT or other filings listed
Cited by0 later documents
SourceGoogle Patents (search for CN112519448B)

What the claims cover, in plain language

Claim 1 defines a folder comprising a curling disc device with a first curling sheet and a second curling sheet. Both are made of elastic material and have a spiral shape. The second sheet is inside the first. They are connected at their tail ends by a connecting plate. A first magnet is fixed to the front side of the first sheet’s tail. A clamping device is placed between the sheets, sliding on rails. Two symmetric limiting devices are on the outer side of the first sheet. Each limiting device includes an elastic limiting plate, a fixing column, and end plates. A fixing groove in the end plate contains a second magnet and a clamping groove. This clamping groove interacts with a corresponding groove on the first curling sheet to lock the position.

Claim 2 details the clamping device further, specifying a clamping strip with a rotary column, torsion springs, and vertical strips that interact with the limiting devices’ grooves to provide mechanical retention.

This is a simplified reading for orientation only. The legal scope is defined by the exact claim wording in the official Chinese document.

What this means for US production

This patent was filed only in China and is currently in force. Therefore, making, selling, or importing products that fall within the scope of these claims in China requires permission from the patent owner. There is no direct restriction on manufacturing in the US based solely on this Chinese patent, as patents are territorial.

Two points to settle early:

  • Other patents may exist. Office supplies and binding mechanisms are a crowded field. While this specific dual-spiral magnetic design appears unique in the current search, prior art regarding magnetic closures, spiral binders, and sliding clamps exists globally. A freedom-to-operate (FTO) review is recommended to ensure no other US patents cover similar functional aspects (e.g., specific magnet placement or clamp mechanics).
  • Material sourcing. The patent specifies “elastic material” for the sheets. Sourcing consistent, durable elastomers or polymers that hold a spiral shape while remaining flexible enough for daily use is a key engineering challenge for US manufacturers.

Customization and manufacturing

What can be customized

AreaOptions
Spiral DiameterAdjusted based on the intended page count and folder size (A4, Letter, etc.).
MaterialChoice of elastic polymer (TPU, silicone blends, or reinforced plastics) for durability and feel.
Magnet StrengthN52 neodymium magnets for strong hold, or ferrite for cost reduction.
Color & FinishMatte, glossy, or textured surfaces; custom colors for branding.
Clamp MechanismSimplified versions of the sliding clamp for lower-cost models.
SizeCustom dimensions for specific document types (legal, passport, receipt books).

Things to plan for (US market)

  • ASTM F963 - Consumer Product Safety Improvement Act (CPSIA) requirements if marketed towards children or schools. Small parts regulations apply due to magnets and screws.
  • California Prop 65 - Screening for lead, cadmium, and phthalates in plastics and coatings.
  • FDA Compliance - If used for food-related documentation or in healthcare settings, materials must be non-toxic and easy to clean.
  • Recycling Standards - Multi-material designs (plastic + metal magnets) can complicate recycling; consider mono-material options for eco-friendly branding.

How a project runs

  1. Inquiry - Define target folder size, capacity, and material preferences.
  2. Design - CAD modeling of the spiral pitch, magnet placement, and clamp tolerances.
  3. Prototype - 3D printing or CNC machining of the spiral shells and injection molding samples for the connectors.
  4. Pilot run - Testing magnetic retention strength, fatigue life of the elastic material, and ease of opening/closing.
  5. Production - Injection molding for the spiral sheets and hardware, assembly of magnets and clamps, quality control checks.

Quantities & timeline

Tooling for spiral shapes requires precision molds to ensure smooth rolling without binding. Magnets must be inserted accurately during molding or glued post-production. Cycle testing for the elastic recovery of the sheets is critical. Send us your target size, material preference, quantity, and desired features and we will reply with options.

Patent drawings

Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 1
Fig. 1 - Perspective view of the folder in closed state.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 2
Fig. 2 - Cross-sectional view showing the dual spiral arrangement.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 3
Fig. 3 - Exploded view of the curling disc device.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 4
Fig. 4 - Detail of the connecting plate and magnet.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 5
Fig. 5 - Structure of the limiting device.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 6
Fig. 6 - Interaction between the limiting device and the curling sheet.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 7
Fig. 7 - Detailed view of the clamping groove.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 8
Fig. 8 - Internal structure of the clamping device.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 9
Fig. 9 - Alternative embodiment of the clamp.
Spiral Elastic Folder with Magnetic Closure and Sliding Clamp - Patent Fig. 10
Fig. 10 - Operational diagram of the sliding rails.

Drawings reproduced from the public patent document for reference.

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  1. ✓ Patent vetted China-only family and legal status checked
  2. 2 Product brief · now How it works, uses and options written up
  3. 3 Prototype First samples for buyers to review
  4. 4 Pilot run Small first batch for launch customers
  5. 5 Volume production Repeat orders at scale

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This page is based on the public patent document CN112519448B, assigned to Shandong Lunan Big Data Industry Development Co ltd. IP2M is an independent manufacturing service and is not affiliated with, endorsed by or licensed by the patent owner. Images marked as concept renderings are illustrations, not photos of an existing product. Patent status information is provided for reference only and is not legal advice; confirm freedom to operate for your market before production. Full disclaimer.